The common causes of sticky phlegm in the throat and coughing are chronic laryngitis, postnasal drip syndrome and gastroesophageal reflux disease. 1. Chronic pharyngolaryngitis: repeated inflammatory stimulation, causing chronic inflammation of the mucous membrane of the pharynx, resulting in lymphoid follicular hyperplasia, increased glandular secretion, mucous phlegm-like secretions in the throat attached to the posterior wall of the pharynx, coughing. 2. Postnasal drip syndrome: common in sinusitis, rhinitis, etc., easy to cause nasal secretions flow back into the throat, mucous phlegm, always coughing. 3. Gastroesophageal Reflux Disease (GERD): It can be seen in gastric diseases, causing the stomach contents to flow back into the throat, and after corrosion of gastric acid, sticky secretions appear, which cannot be coughed up in the throat. Therefore, it is recommended to consult a doctor in time for the diagnosis and treatment under the guidance of a professional doctor.